The cardiac cycle describes the path of blood through the heart. Deoxygenated blood enters the right atrium from the body and oxygenated blood enters the left atrium from the lungs. The blood then passes through valves into the ventricles before being pumped out - the right ventricle pumps to the lungs while the left ventricle pumps to the body. Valves prevent backflow of blood into the atria and ventricles.

1. Cardiac Cycle: Path of blood through the heart
• The right atrium receives deoxygenated blood from the body through the vena
cava
• The left atrium receives oxygenated blood from the pulmonary vein
• Blood passes through valves from the atria to the ventricles
• Valves prevent the backflow of blood into the atria

2. • The right ventricle pumps deoxygenated blood to the lungs through the
pulmonary artery
• The left ventricle pumps oxygenated blood to the rest of the body through the
aorta
• Valves prevent back flow into the ventricles